How Much Are We Polluting the Oceans?

The oceans are suffering from overfishing and plastic, oil, chemical and other pollutants. Thought leisure boating is not the biggest source of these problems, the boating community has a responsibility to evaluate and optimize its environmental impact. First on the agenda is a look at how marine activities strain the ocean environment.

The UK Marine Protected Areas Centre is a British resource center for news and information concerning protected maritime areas. Some years back, they put together a summary of the potential impacts of waterborne recreation—basically leisure boating. The list includes engine emissions, noise pollution, antifouling paint, waste discharge, disturbance of wildlife, erosion and turbidity.

Engine emissions primarily concern two-stroke outboards, which use technology essentially unchanged since the 1940s. A 2010 study by US scientist Russell Long indicates that worldwide, such pollution amounts to 15 times that of the Exxon Valdez oil spill of 1989.

Conventional two-stroke engines discharge as much as 30% of their oil-fuel mix into the water unburned. This justifies the increasing bans on this type of outboard. However, modern two-strokes can easily pass new emissions tests and will remain on the market. Today, the main problem is that older two-stroke engines tend to end up in Africa and other areas where poverty and weak regulations will keep them in use for years to come.

The Dangers of Antifouling Paint

When it comes to antifouling, copper and tributyltin (TBT) are the main threats to sea life. TBT is a powerful biocide with well documented negative effects, but the real risks of copper are less certain.

Antifouling (Courtesy of J. B. Chandlery)

While regulations elsewhere become stricter every year, developing countries lag behind. More eco-friendly replacement additives for antifouling have so far struggled to equal the effectiveness of copper or TBT. And boats with more barnacles under the waterline consume more fuel.

According to PYA, the Professional Yachting Association, grey water containing detergents, bleach and other substances is another major culprit when it comes to water pollution. In contrast, blackwater from toilets is biologically degradable.

PYA suggests that the two be contained and treated in separate systems. Discharge with very high or low pH can cause major damage to ocean life, especially in areas with reduced water movement. The problem is even worse in areas with low levels of dissolved oxygen and high levels of nutrients.

Noise Pollution for Whales and Dolphins

Noise pollution is an often-overlooked negative factor for oceanic biodiversity. Captain Paul Watson, founder and CEO of the international marine wildlife conservation non-profit, Sea Shepherd, explains: “The sounds of ships and motorboats permeate the sea. And because sound travels long distances in the ocean, it interferes with the communication and navigation of whales, dolphins, tortoises and many fishes.”

The sounds of ships and motorboats permeate the sea and interfere with the communication of dolphins (Courtesy of Penguin Random House)

Moreover, watercraft in the broadest sense—especially speed boats, jet skis, SUPs and canoes—can easily get close to seabirds and animals. Usually, this is not a problem. But some species are very sensitive when breeding. Close encounters can interfere with the breeding process, even preventing new offspring from surviving.

According to Watson, collisions also kill thousands of slow-moving sea animals every year, among them whales, turtles and manatees. The main danger is from fast, planing powerboats. Limiting speed and avoiding breeding areas during the reproductive period could reduce these effects significantly.

Erosion and turbidity are localized problems. Anchors, anchor chains and propeller wash can seriously damage the seabed, especially coral reefs. Of course, the most beautiful places are also the most visited. According to marinecultures.org, an environmental organization based in Switzerland, the use of permanent moorings can alleviate the problem.

Big Ships = Big Problems

The commercial shipping industry pollutes thousands of times more than recreational boating. However, it is far less regulated due to its powerful lobby and financial weight.

Cruise ship pollution (Courtesy of NABU/Wattenrat/E. Voss)

Still, Sea Shepherd’s Watson encourages the use of sail, paddle and oar—anything not propelled by an engine. “Sailing boats contribute very little to the problems we are dealing with here. And in the big picture, pleasure vessels as a whole represent an insignificant impact compared to the destruction and pollution caused by fishing boats and large commercial ships.”